1. Field of the Invention
The present invention relates to chemical production procedures and more particularly to methods of making a suspension of a filler for rubber mixtures. The invention may prove most advantageous in the production of products from filled rubbers and other elastomers.
2. Description of the Prior Art
Known in the art is a method of making a disperse filler for rubber mixtures as described in U.S. Pat. No. 3,966,487. The method comprises the steps of pyrolyzing the waste products of polymeric materials at a temperature of from 425.degree. to 1,370.degree. C. for carbonization thereof and grinding the carbonized mass. As a result, carbon black is obtained which can be used as a filler for the production of tires and othe rubber products.
It is to be noted that in the course of the pyrolysis the valuable hydrocarbons contained in the waste products being treated are irreparably lost. In addition, the finely divided carbon black (essentially powder) requires prolonged stirring and homogenization when introduced in a dry state into the rubber mixtures being produced.
More preferable in the production of filled rubbers is the use of a suspension of a filler in a solvent. In particular, known in the art is a method of making a suspension of a filler by dispersing carbon black in a mixture of mineral oil and liquid hydrocarbon, and then introducing divinyl styrene rubber in liquid hydrocarbon (see USSR Inventor's Certificate No. 401,685).
It is simpler to introduce thus obtained suspension of a filler into the rubber mixtures being produced. However, the use of the scarce raw material makes the production process more expensive. In addition, toluene used in this process as a solvent is a toxic and dangerously explosive raw material. The attempts to make the above production procedure less expensive by using cheaper solvents were without success because of a substantial decrease in the quality of the end product.
The object of the present invention is to provide a method of making a suspension of a filler wherein the raw material and the parameters of the production procedure are selected so as to make it possible to do without scarce and costly materials and at the same time to upgrade the quality of the end product.